In a hub-and-spoke network topology, a repeater resides on a hub. The repeater facilitates an exchange of data packets among a number of clients. A client can be a computer, a facsimile machine, another computer, etc. The repeater serves several ports where each port is connected to an individual one of the clients with a separate point-to-point link between the repeater and such client.
In a 100BASE-TX signalling protocol, unshielded twisted pairs of wires constitute the point-to-point link between the repeater and each of the clients. Each link consists of two pairs of unshielded twisted wires. One pair of the unshielded twisted wires provides for a transmission of data from the repeater to an individual one of the clients. The other pair of the unshielded twisted wires provides for a transmission of data from the individual one of the clients to the repeater.
When information is illustratively transmitted from the repeater to an individual one of the clients in a 100BASE-TX system, the information is originally in digital form. The digital information may represent individual ones of a plurality of analog levels. Specifically, in a 100BASE-TX System, the digital signals may represent analog levels of +1, 0 and −1.
The digital information at the repeater may be converted to analog form and then transmitted in analog form through the unshielded twisted pair of wires to the individual one of the clients. The transmitted signals are received in analog form at the individual one of the clients. The received signals are then processed to recover the transmitted information represented by the analog information.
The distance between the repeater and the individual one of the clients may be as great as one hundred meters. The unshielded twisted pair of wires coupling the repeater and the individual one of the clients produces a degradation in the characteristics of the signals as the signals pass through the unshielded twisted pair of wires. The amount of the degradation rapidly increases with increases in the length of the unshielded twisted pair of wires connected between the repeater and the individual one of the clients.
The degradation results in part from Inter Symbol Interference (ISI), signal attenuation, crosstalk, clock jitter and a number of other factors. Such degradation severely distorts the transmitted data signals. The degradation also results in part from the fact that the analog information transmitted from the repeater to the individual one of the clients is also received at the other clients connected to the repeater and is reflected back to the repeater, thereby affecting the characteristics of the signals transmitted from the repeater to the individual one of the clients.
Analog techniques have been used in the prior art to process the analog signals received at the individual one of the clients. These analog techniques have not been completely effective in eliminating the degradation or distortions in the signals received at the individual one of the clients. This has caused errors to be produced in the information received and processed at the individual one of the clients. This has been true even though the 100BASE-TX system provides substantially greater noise immunity than other types of systems and is able to handle smaller signal levels than other types of systems.